Although it is widely recognized that environmental factors such as smoking, diet, exercise, and socioeconomic status affect the risk of cardiovascular disease, recent work showing the effects of other environmental factors provides a more complete assessment of the situation. This view has emerged from three developments. Firstly, there has been a sudden explosion in the prevalence of diabetes and obesity which indicates a strong environmental component. Secondly, there is an accumulation of evidence suggesting that most cases of these diseases could be prevented by healthy lifestyle choices.